FLOOD02750

• Document ID: 125
• County: Routt
• Stream Name: Elk River
• Basin: Yampa/White
• Water Division: 6
• Title: Streambank Stabilization Limited Watershed
• Date: 11/1/1999
• Prepared For: CWCB
• Prepared By: ICON Engineering, Inc.
• Watershed Pro - Doc Type: Educational/Technical/Reference Information

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2.2.2 Steamboat Lake

The State of Colorado Division of Parks and Outdoor Recreation operates Steamboat Lake as a
recreation facility, From discussions with maintenance personnel, the lake level is set for
maximum recreational use, and release rates from the lake are based on an effort to maintain a
condition where inflow equals outflow, In periods of low flow for the Elk River basin, the
release rates from the lake are coordinated with the Division of Wildlife to ensure adequate low
flow levels are maintained in the Elk River. The lake is known for its exceptional fisheries
quality. This is partially attributed to the number of main tributaries feeding the reservoir. A
copy of the June 20, 1999 article on fishing at Steamboat Lake by Ed Denton of the Denver
Rocky Mountain News is included in Appendix C.

The NRCS has one snotel gage (C006JI5S) for the Elk River basin that is located in the
Willow Creek basin above Steamboat Lake, ICON obtained daily snow water equivalent data
for the months of April, May, and June in 1993, 1995, 1997 and 1998 from the NRCS, An
estimated water content of the snowpack above Steamboat Lake for these months and years are
summarized in Table 2,3, The drainage area used for these estimates was the 35.5 square mile
drainage area for the Willow Creek below Steamboat Lake gage site, Mean monthly values for
the snow water equivalent were used for this estimate, Other assumptions included uniform
snowfall over the tributary drainage area, and that the area of snow coverage was equal to the
drainage area. The water content estimated for the season was determined by taking the
maximum value for the three-month period for each year. A copy of the supporting
information is included in Appendix D,

TABLE 2,3
Estimation of Water Content Above Steamboat Lake

DATE

Mean Snow
Water Equivalent
inches
21,03
18,27
27,74
16,72

Mean Water
Volume
ac-ft
39,820
34,590
52,520
31,660

1993 - April
1995 - May
1997 - April
1998 - April

Streamflow data was obtained from the State of Colorado Division of Water Resources for the
Willow Creek below Steamboat Lake gage site, This data provided daily discharge values for
the lake releases, For the runoff season (April, May, and June) of both 1997 and 1998, the
Steamboat Lake outflow hydrographs were taken from this gage data, With only daily values
available and due to our understanding of operation practices, it was assumed that the flow was
constant for a 24-hour period. A corresponding inflow hydro graph was estimated based on
four main factors: I) the volume of the outflow hydrograph for the season; 2) the minimum
lake level recorded by the River Commissioner for period preceding the runoff season; 3) the
elevation versus volume curve from the original plans for the Willow Creek Reservoir Dam;
and 4) operation of the lake outlet works is based on inflow equal to outflow near the lake level
that provides optimal recreational use. Ordinates of the inflow hydrograph were adjusted until

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